风电并网系统中长期过程仿真研究

发布时间：2018-08-09 13:08

【摘要】：风力发电作为新能源领域中技术最为成熟的电源,现在已经成为全球新能源发展的主力。由于风能具有波动性和随机性的特点,所以经风力发电系统转换而成的电能也是不稳定的,随着风电场装机规模的扩大以及单台风机容量的增加,风力发电系统对电网的稳定运行和安全调度会造成很大的影响。因此,有必要建立风电场的中长期过程仿真模型,以便评估风力发电系统对电网造成的影响,同时为风电场的规划和风电调度提供依据。本文以双馈风力发电系统为研究对象,分别对其进行了运行原理分析、变流器前馈功率控制、系统中长期建模仿真等研究工作。首先,本文详细介绍了双馈风力发电系统的各个组成部分,包括风速数学模型、风轮机和传动系统数学模型、双馈风力发电机数学模型和变流器数学模型。然后,本文由瞬时功率理论入手,引出了变流器的直接功率控制策略,介绍了有功功率和无功功率的解耦控制,针对电网电压变化时系统响应时间长,容易引发不稳定等问题,本文提出了功率前馈控制策略；并在PSCAD/EMTDC中建立了变流器的功率前馈控制仿真模型,对所提方法进行了验证,仿真结果表明功率前馈控制策略能够有效的提高系统的动态性能。中长期建模目的是为了反映风电场对电网造成的影响,这就不需要详细复杂的双馈发电机和变流器精确模型,本文由双馈风力发电机和变流器的工作特性,提出了采用三相可控电流源替代发电机和变流器的建模方法,并给出了双馈风力发电系统中长期仿真中各个部分的模型,包括发电机和变流器模块、变流器控制模块、风轮机模块和桨距角控制模块；同时提出了风电场模型并网控制策略,保证了模型输出功率的精确性和快速性。在PSCAD/EMTDC中搭建了双馈风力发电系统中长期过程仿真模型,仿真结果验证了所建双馈风力发电系统中长期仿真模型的合理性和正确性。
[Abstract]:As the most mature power source in the field of new energy, wind power generation has become the main force in the development of new energy. Because wind energy has the characteristics of volatility and randomness, the electric energy converted by wind power system is also unstable. With the expansion of wind farm installation scale and the increase of single typhoon capacity, Wind power generation system will have a great impact on the stable operation and safe dispatching of power grid. Therefore, it is necessary to establish a long-term process simulation model of wind farm in order to evaluate the impact of wind power system on power grid, and to provide the basis for wind farm planning and wind power dispatching. In this paper, the doubly-fed wind power generation system is taken as the research object, and its operation principle analysis, feed forward power control of converter, modeling and simulation of the system are carried out respectively. Firstly, every component of the doubly-fed wind power generation system is introduced in detail, including wind speed mathematical model, wind turbine and transmission system mathematical model, doubly-fed wind generator mathematical model and converter mathematical model. Then, based on the instantaneous power theory, the direct power control strategy of the converter is introduced, and the decoupling control of active power and reactive power is introduced. In this paper, the power feedforward control strategy is proposed, and the power feedforward control simulation model of the converter is established in PSCAD/EMTDC, and the proposed method is verified. The simulation results show that the power feedforward control strategy can effectively improve the dynamic performance of the system. In order to reflect the influence of wind farm on power grid, the long-term modeling purpose is not to need the detailed and complicated exact model of doubly-fed generator and converter. In this paper, the working characteristics of doubly-fed wind turbine and converter are discussed. The modeling method of replacing generator and converter with three-phase controllable current source is put forward, and the models of each part in the simulation of doubly-fed wind power system are given, including generator and converter module, converter control module. The wind turbine module and the pitch angle control module are also proposed, and the wind farm model grid-connected control strategy is proposed to ensure the accuracy and rapidity of the output power of the model. A long-term simulation model of doubly-fed wind power generation system is built in PSCAD/EMTDC. The simulation results verify the rationality and correctness of the model.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614

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